Polymerization of oxirane



United States Patent Ofiice 3,127,371 Patented Mar. 31, 196% 3,127,371 PQLYMERHZATIUN 01h flXmANE MUNQEPUXEDEd Kenneth T. Garry, Semervilie, and Thomas B. Gibb, Jr.,

Murray Hill, N..l., assignors to Union Carbide Corporation, a corporation of New York No Drawing. Filled July 1, 1959, Ser. No. 824,193 17 tllairns. (ill. 260-47) This invention relates to the polymerization of oxirane monoepoxide monomers. More particularly, this invention relates to an improved method of polymerizing oxirane monoepoxide monomers whereby relatively high conversions of monomer to polymer are effected in relatively short periods of time.

Polymerization of oxirane monoepoxides in the presence of an organometallic compound, such as dibutyl zinc, which serves as a catalyst for the polymerization reaction, has been found to be desirable as the polymers produced are hard, tough solids which are useful in the manufacture of various shaped articles and in the preparation of film material which can be used in the manufacture of bags, wrapping material, and the like. Moreover, the organometallic compound remaining in the polymer at the termination of the polymerization reaction can be converted into an inert, non-deleterious residue, which can be left in the polymer if so desired, by a simple operation wherein the polymer is contacted with water or an alcohol such as ethyl alcohol. Consequently, solid polymers produced by polymerizing an oxirane monoepoxide in the presence of an organometallic compound do not require any elaborate and time consuming purification operations in order to remove catalyst residue therefrom.

The extensive use of organometallic compounds as catalysts for the polymerization of oxirane monoepoxides to produce solid polymers has been seriously limited, however, due to the relatively long periods of time required in order to obtain any significant polymer yields. In addition, it has not been possible to obtain reproducible yields of solid polymer using organo-metallic compounds as catalysts. Yields obtained have varied from batch to batch and have been relatively small.

The present invention provides for the production of oxirane monoepoxide polymers by polymerizing a monomeric oxirane monoepoxide and mixtures thereof in the presence of an organometallic compound and also in the presence of a controlled amount of a ketone, which serves as a promoter for the polymerization reaction, whereby relatively high conversions of monomer to polymer are effected in a relatively short period of time. Moreover, the presence of a controlled amount of a ketone in the polymerization reaction allows for reproducibility of polymer yields.

The amount of ketone employed in the polymerization reaction can vary from about 0.01 to about 3 moles per mole of the organometallic compound. Optimum results are achieved at a mole ratio of ketone to the organometallic compound of about 0.5:1 to about 2.4:1.

Any aromatic or aliphatic ketone, free of interfering functional groups, such as an ester group, an acid group, an aldehyde group, and an amino group, can be used as a promoter for the polymerization of an oxirane monoepoxide in accordance with the present invention. Particularly desirable ketones are those wherein one of the hydrocarbon groups attached to the bivalent ketonic group is an aliphatic, saturated hydrocarbon group having up to carbon atoms. Illustrative of suitable mono ketones can be noted dimethyl ketone, methylethyl ketone, methyl propyl ketone, methyl octyl ketone, methyl nonyl ketone, methyl phenyl ketone, methyl naphthyl ketone, diethyl ketone, ethyl methyl ketone, ethyl isopropyl ketone, ethyl butyl ketone, ethyl isobutyl ketone, ethyl isoamyl ketone, ethyl hexyl ketone, ethyl heptyl ketone, ethyl phenyl ketone, ethyl naphthyl ket-one, dibutyl ketone, isoamyl phenyl ketone, isoamyl methyl ketone, dipentyl ketone, dihexyl ketone, hexyl methyl ketone, hexyl propyl ketone, diheptyl ketone, heptyl methyl ketone, diundecyl ketone, dihendecyl ketone, diheptadecyl ketone, and the like.

The term polymer as used herein is intended to encompass homopolymers, as well as copolymers and interpolymers produced by polymerizing a mixture containing two or more monomeric oxirane monoepoxides.

Organometallics which can be employed as catalysts for the polymerization of oxirane monoepoxides to produce solid polymers are compounds whose compositions can be represented by the formula:

wherein Me is a metal of group II of the periodic table, i.e., beryllium, magnesium, calcium, zinc, strontium, cadmium, barium, mercury, and radium; and wherein R and R are hydrocarbon radicals such as alkyl, aryl, aralkyl, alkaryl, and cycloalkyl. Particularly desirable organometallics are those compounds having the structural formula noted above wherein R and R are hydrocarbon radicals having from 1 to 10 carbon atoms and being free from olefinic and acetylenic unsaturation.

Representative R and R radicals include, among others, methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, Z-ethylhexyl, dodecyl, octadecyl, phenyl, tolyl, Xylyl, benzyl, phenethyl, phenyipropyl, phenylbutyl, cyclopentyl, cyclohexyl, cycloheptyl, 3-propylcyclohexyl, and the like. Illustrative of organometallic compounds which can be used as catalysts can be noted diethyl zinc, dipropyl zinc, di-n-butyl zinc, dioctadecyl zinc, dicyclohexyl zinc, diphenyl zinc, di-o-tolyl Zinc, diethyl magnesium, di-n-butyl magnesium, dioctyl magnesium, diphenyl magnesium, diethyl beryllium, di-n-butyl beryllium, diethyl cadmium, dipropyl cadmium, diisoamyl cadmium, diphenyl cadmium, and the like. The organometallics are known compounds and can be prepared according to the methods described in Berichte, 63, 1138 (1934); 59, 931 (1926). The organometallic compounds are generally used in catalytic amounts, that is, in amounts sufiicient to catalyze the polymerization of oxirane monoepoxides to solid polymers. The actual quantity of organometallic compound used can be varied between wide limits, for example, from about 0.01 to about 12 percent by weight and higher, based on the Weight of the monomer charged. It is preferred to use an amount of catalyst ranging from about 0.1 to about 3 percent by weight.

The term oxirane monoepoxide as used herein is intended to encompass those compounds having a single terminal epoxy group, i.e.:

. epoxyphenyl ethane, 1,2 epoxy-p-methylphenyl-ethane,

a \b 1,2-epoxy-o-chlorophenyl ethane, and the like; epoxyalkyl ethers, such as those having the structural formula OHz-CH--RO-R wherein R is a hydrocarbon radical such as alkyl, aryl, alkaryl, aralkyl, and the like, and wherein R is a saturated aliphatic hydrocarbon radical. Particularly desirable polymers are those produced by polymerizing a monomer having the structural formula noted above wherein R contains from 1 to 4 carbon atoms and R is a phenyl or alkyl substituted phenyl radical wherein the alkyl substituent contains up to 12 carbon atoms. Illustrative radicals for R include, among others, methylene, ethylene, propylene, butylene, hexylene, octylene, and the like. Representative radicals for R include, among others, phenyl, 2-, 3-, and 4-methylphenyl, 4-isopropylphenyl, 4- tertiarybutylphenyl, 4-octylphenyl, ethyl, propyl, butyl, amyl, and the like.

Suitable epoxyalkyl ethers include the following:

1,2-epoxy-3-phenoxy-propane, l,2-epoxyl-phenoxy-butane, 1,2-epoxy-S-phenoxy-pentane, 1,2-epoxy-6-phenoxy-hexane,

1,2-epoxy-3- (o-methylphenoxy -propane, 1,2-epoxy-3- (m-methylphenoxy) -propane, 1,2-epoxy-3-(p-methylphenoxy) -propane, 1,2-epoxy-3- o-isopropylphenoxy) -propane, 1,2-epoxy-3- (p-tertiary butylphenoxy -propane, 1,2-epoxy-3- (p-octylphenoxy) -propane, 1,2-epoxy-3-(o-chlorophenoxy)propane, 1,2-epoxy-3- (o-chlorophenoxy) -propane, 1,2-epoxy-3-(2,4-dimethylphenoxy) -propane, 1,2-epoxy-3- 2, S-dimethylphenoxy) -prop ane, 1,2-epoxy-3- 2,6-dimethylphenoxy -propane, 1,2-epoxy-3- (2-chloro-4-methylphenoxy) -propane, 1,2-epoxy-3- (o-amylphenoxy) -propane, 1,2-epoxy-4- (o-methylphenoxy) -butane, 1,2-epoxy-4- (2,4-dimethylphenoxy) -butane, 1,2-epoxy-4- 2,5 -dimethylphenoxy -butane, 1,2-epoxy-4- (2,4-dichlorophenoxy) -butane, 1,2-ep oxy-4- (2,5 -dichlorophenoxy) -butane, 1,2-epoxy-6-phenoxy-hexane, 1,2-epoxy-6-(2,3-dibromophenoxy) -hexane, and the like.

The polymerization reaction is conducted by charging an oxirane monoepoxide monomer or mixture of monomers, an organometallic compound and a controlled amount of a ketone in a reaction vessel and generally subjecting the reaction vessel to heat. Actually, the temperatureat which the polymerization reaction is conducted can be varied over a wide temperature range, from about 0 C. to about 200 C., and, if desired, even higher. A temperature in the range of about 60 C. to about 175 C. is most preferred.

It is also preferred to conduct the polymerization reaction in the presence of an organic diluent which is nonreactive with respect to the monomer, catalyst, and polymer, is a solvent for the monomer and catalyst mixture, but a non-solvent for the polymer. During the polymerization reaction, particularly whenever about 50 percent or more of the monomer is converted to the polymer, the reaction mixture becomes highly viscous. If a diluent is not present, it is difficult to remove the heat of reaction which, if not removed, might cause undesirable side reactions to occur. In addition, the use of a diluent facilitates removal of unreacted monomer from the polymer.

Illustrative of suitable organic diluents can be noted the aromatic hydrocarbons, such as benzene, chlorobenzene, toluene, xylene, and the like; cycloaliphatics, such as cyclopentane, cyclohexane, isopropyl cyclohexane, and the like; alkoxy compounds, such as methoxybenzene and the like; the dimethyl and diethyl ethers of ethylene glycol, propylene glycol, diethylene glycol; aliphatics, i.e. hexane.

The diluent can be added prior to the commencement of the polymerization reaction or during the polymerization reaction in amounts of from about 5 to parts by weight per parts by weight monomer and diluent.

The polymerization reaction is preferably conducted under an inert atmosphere, e.g., nitrogen, and can be under atmospheric, sub-atmospheric, or super-atmospheric pressures.

The time required to polymerize an oxirane monoepoxide to produce a solid polymer will vary and depend upon a number of factors such as the temperature at which the polymerization reaction is being conducted, the amount of and nature of the organometallic catalyst used, and also upon the nature of the monomer employed. Using a ketone as a promoter in accordance with the present invention, relatively high yields of polymer have been obtained in as short a time as four hours.

The crude product resulting from the polymerization reaction usually contains, in addition to the solid polymer, some unreacted monomer, and also catalyst residue. Removal of the unreacted monomer and catalyst residue can be accomplished by any convenient manner. If desired, the catalyst residue can be left in the polymer after first treating the polymer with water or an alcohol, such as ethyl alcohol. For instance, when dibutyl zinc is the catalyst used and it is desired to allow the catalyst residue to remain in the polymer, the polymer is conveniently treated with ethyl alcohol whereby the catalyst is converted to its oxide, which oxide is inert and does not have any deleterious effect on the polymer. The ethyl alcohol is driven from the polymer by applying heat thereto. When it is desired to remove both unreacted monomer and catalyst residue from the polymer produced, as for example poly(1,2-epoxy-3-phenoxy-propane), the crude product is dispersed in a mixture of acetone and hydrochloric acid, the dispersion is then filtered, thereby obtaining the polymer as a filter cake and, if necessary, then washing the polymer with small amounts of ethyl alcohol to obtain a white colored solid. Unreacted monomer and catalyst residue can be removed from a polymer such as po1y( l,2 epoxyethane) by dissolving the crude product in ethyl alcohol, filtering ofi the catalyst residue, concentrating the solution to remove the alcohol and recovering the polymer. In general, it is desirable to remove the unreacted monomer from the crude product as the polymer recovered exhibits enhanced thermal and dimensional sta bility.

The percent conversion of monomer to polymer as noted herein was determined by removing the unreacted monomer and catalyst residue from the polymer, drying the polymer to a constant weight at a temperature of from about 50 C. to 60 C. under a pressure of 25 mm. Hg, weighing the polymer, dividing the weight of the polymer by the weight of the monomer charged, and multiplying by 100.

In the following examples, which are illustrative of the present invention and not intended to limit the scope thereof in any manner, the reduced viscosity measurements, which are a measure of the molecular weight, were made as follows.

A 0.05 gram sample of polymer was weighed into a 25 ml. volumetric flask and p-chlorophenol containing 2 percent by weight pinene added thereto. The flask was heated for 30 minutes in an oil bath maintained at C. with intermittent swirling. After solution was complete, additional p-chlorophenol containing 2 percent by weight pinene Was added to produce a 25 ml. solution while maintaining the flask in a 47 C. constant temperature bath. The solution was thereafter filtered through a sintered glass funnel and the viscosity of a 3 ml. sample determined in a Cannon viscometer at about 47 C.

Reduced viscosity was computed by use of the equation:

ts-to RT cto Where Example 1 To each of two Pyrex glass tubes which had been flushed out with nitrogen gas there was charged 7.33 grams of 1,2-epoxy-3-phenoxy-propane and a solution of 0.11 gram of dibutyl zinc in 21.2 ml. of toluene. To one of the tubes there was also added acetone in an amount to provide a mole ratio of acetone to dibutyl zinc of 1:1. Both tubes were provided with a nitrogen gas atmosphere, sealed and heated at 90 C. for four hours in an air circulating oven. Each tube was then broken open and the contents thereof transferred to a Waring Blender using 200 ml. of a mixture (50-50 on a volume basis) of acetone and toluene acidified with 5 m1. of 1 N hydrochloric acid. After thorough agitation in the Waring Blendor, the mixture was poured into ethyl alcohol. The amount of ethyl alcohol was 100 times the volume of the mixture. The polymer precipitated out of the ethyl alcohol and was recovered as a filter cake. The polymer was then washed with small quantities of ethyl alcohol, dried at 60 C. for 24 hours under a pressure of 25 mm. Hg and then dried an additional 24 hours at a temperature of from 40 C.60 C. and under a pressure of 25 mm. Hg.

The percent conversion of monomer to polymer, the mole ratio of acetone to dibutyl zinc, and the reduced viscosity of the polymer obtained are noted in the table below.

Mole ratio of acetone to dibutyl zinc. Percent conversion 1. Reduced viscosity To each of eight Pyrex glass tubes which had been flushed out with nitrogen gas there was charged 7.52 grams of 1,2-epoxy-3-phenoXy-propane and a solution of 0.11 gram of dibutyl zinc in 21.2 ml. of toluene. To all but one of the tubes there was added acetone in amounts sufficient to provide a mole ratio of acetone to dibtuyl zinc as indicated in the table below. The tubes were provided with a nitrogen gas atmosphere, sealed, and heated at 90 C. for 16 hours in an air circulating oven. A solid white colored polymer was recovered from each tube in a manner described in Example 1.

What is claimed is:

1. Method for the production of a polymer of an epoxide compound which comprises polymerizing a monomeric oxirane monoepoxide, which is free of ester, acid, amino and aldehyde groups, a reaction medium containing at least about 0.01 percent by weight, based on the weight of said monoepoxide, of an organometallic compound having the formula:

wherein R and R are hydrocarbon radicals and :Me is a metal of group II of the periodic table, and containing from about 0.01 to about 3 moles of a mono ltetone, free of ester, acid, amino and aldehyde groups per mole of said organoinetallic compound.

2. Method as defined in claim 1 wherein the polymerization reaction is conducted at a temperature of from about 60 C. to about C.

3. Method as defined in claim 1 wherein the said organometallic compound is present in an amount of from about 0.01 to about 12 percent by weight based on the weight of the said monoepoxide.

4. Method as defined in claim 1 wherein the said organometallic compound is dibutyl zinc.

5. Method as defined in claim 1 wherein the said monoepoxide is 1,Z-epoxy-3-phenoxy-propane.

6. Method as defined in claim 1 wherein the said ketone is present in an amount of from about 0.5 to about 2.4 moles per mole of the said organometallic compound.

7. Method as defined in claim 1 wherein the polymerization reaction is conducted at a temperature of from about 0 to about 200 C.

8. Method as defined in claim 1 wherein the said organo-metallic compound is present in an amount of from about 0.1 to about 3 percent by weight, based on the weight of said monoepoxide.

9. Method as defined in claim 1 wherein the said ketone is acetone.

10. Method as defined in claim 3 wherein the said hetone is present in an amount of from about 0.5 to about 2.4 moles per mole of said organometallic compound.

11. Method for the production of a polymer of an epoxide compound which comprises polymerizing at a temperature of from about 0 C. to about 200 C., a monomeric oxirane monoepoxide, which is free of ester, acid, amino and aldehyde groups, and which is selected from the group consisting of epihalohydnins, olefine oxides and a compound having the formula:

wherein R is a saturated aliphatic hydrocarbon radical and R is a hydrocarbon radical, in a reaction medium containing from about 0.0 1 to about 12 percent by weight, based on the weight of said monocpoxide, of an orgauometallic compound having the formula wherein R and R are hydrocatnbon radicals and Me is a metal of group II of the periodic table, and containing from about 0.01 to about 3 moles of a mono ketone, free of ester, acid, amino and aldehyde groups, per mole of said organometallic compound.

12. Method for the production of a polymer of an epoxide compound which comprises polymerizing at a temperature of from about 60 C. to about 175 C. a monomeric oxirane monoepoxide, which is free of ester,

acid, amino and aldehyde groups, in a reaction medium containing from about 0.1 to about 3 percent by weight, based on the weight of said monoepoxide, of an organometallic compound having the formula:

wherein R and R are hydrocarbon radicals and Me is a metal of group: II of the periodic table, and containing from about 0.5 to about 2.4 moles of a mono ketone, free of ester, acid, amino and aldehyde groups, per mole of said organometallic compound.

13. Method for the production of a polymer of an epoxide compound which comprises polymerizing a monomeric oxirane monoepoxide which is free of ester, acid, amino and aldehyde groups, at a temperature of from about C. to about 200 C., in a reaction medium containing; an organic diluent, from about 0.01 percent by weight to about 12 percent by weight, based on the weight of said monoepoxide, of an organometallic compound having the formula:

wherein R and R are hydrocarbon radicals having from 1 to carbon atoms and being free of olefinic and acetylenic unsaturation, and Me is a metal of group II of the periodic table and from about 0.0 1 to about 3 moles of a monoketone, which is free of ester, a'cid, amino and aldehyde groups, per mole of said organornetallic compound wherein one of the hydrocarbon groups attached to the bivalent ketonic group is an aliphatic, saturated hydrocarbon group having up to 10 carbon atoms.

14. Method as defined in claim 13 wherein the polymerization reaction is conducted at a temperature of from about C. to about C.

15. Method as defined in. claim 13 wherein the said organometallic compound is present in an amount of from about 0.1 to about 3 percent by weight based on the weight of said monoepoxidc.

16. Method as defined in claim 13 wherein the said ketone is present in an amount of from about 0.5 to about 2.4 moles per mole of said organometallic compound.

17. Method as defined in claim 13 wherein the said ketone is present in an amount of 1 mole per mole of said organometallic compound.

References Cited in the file of this patent UNITED STATES PATENTS 2,848,426 Newey Aug. 19, 1958 2,870,100 Stewart et al Jan. 20, 1959 2,881,156 Pilar et al. Apr. 7, 1959 OTHER REFERENCES Schildknecht: Vinyl and Related Polymers, Wiley and Sons, New York, 1952, pages 234 and 424 especially relied upon. 

1. METHOD FOR THE PRODUCTION OF A POLYMER OF AN EPOXIDE COMPOUND WHICH COMPRISES POLYMERIZING A MONOMERIC OXIRANE MONOEPOXIDE, WHICH IS FREE OF ESTER, ACID, AMINO AND ALDEHYDE GROUPS, IN A REACTION MEDIUM CONTAINING AT LEAST ABOUT 0.01 PERCENT BY WEIGHT, BASED ON THE WEIGHT OF SAID MONOEPOXIDE, OF AN ORGANOMETALLIC COMPOUND HAVING THE FORMULA: 